Kobalt brand Torque Wrench

[biggy238]

Well, I started to torque the lug nuts on the rear axle of my truck this evening, and the adjusting handle on my torque wrench just slipped and turned. I had towed heavy and I have one bad wheel from a tire shop screw up.



What makes me really angry is that I used this wrench to torque the head on my truck, and now it has some leaks. It's untelling what torque the head actually has on it. It's a micrometer type. I think maybe it was alright for the retorque on the head studs, but it just makes me wonder.



So, for the record, this wrench is trash.



It's the 25-250ft-lb model 1/2 inch drive micrometer type that cost $89 and change

 

[DAN V]

Husky

I am planning to replace my torque wrench with a HUSKY from home depot. It is the 25 to 250 ft lb range as you speak. And I do believe they are less than 70 bucks. You should take it back and see if they can give you a new one. sounds like it might be defective.

 

[Loghead]

I only use the beam-type torque wrenches, and this is one of the reasons why I will continue to do so.

They're not always as easy to use, but they're simple and reliable. Nothing I've torqued with any of them has ever failed - head bolts, main caps , connecting rods, whatever.



I'm sure there will be lots of conflicting opinion on this, but if your budget has you restricted to Kobalt or Husky (or any of the less-expensive brands), the beam-type torque wrenches are the way to go.

 

[Forrest Nearing]

betting the Husky is the same wrench as the Kobalt is the same as Craftsman. I used to deal with NOTHING but torque equipment... everything from 15in/lb to 2000ftlb clickers to 30,000ftlb hydraulics.



Those cheap wrenches are alright for using a few times, but if you want something that's going to last, get a Snap-On or Proto. Hint, Snap-On's wrenches are made by a company called CDI, and they make wrenches for many different labels.



the split beam are my favorite style. You don't have to back them down after use, and I VERY rarely had to reject one. They hold their calibration very well and they very rarely require more than just minor adjustments if at all.



Precision Instruments - Split Beam Wrenches



yes, that's a snap-on wrench w/ a different label. Only difference is the ratchet head, the internal mechanisms are the same.



CDI makes CAT's wrenches... I think they make wrenches for at least 20 different labels

 

[tgordon]

I tend to agree with Forrest. If I am going to pony up the money for a torque wrench I am going to go with a good quality such as Snap-On, Mac, etc. I went to Sears 4 times and never got a good one#@$%!, that was the end of that junk. I will still go to them for the end wrenchs and such.

 

[nickleinonen]

... at home i have a husky. . it works well enough for what i have done at home. the only thing i torque at home is wheel lugs. everything else is done by hand. at work in the diesel shop, i have a proto 0-150 in my toolbox. it works well and is pretty accurate. at the wheel shop, we have gray torque wrenches. they are pretty accurate as those get checked on a test tool every shift [as per AAR regulations for rail car wheels] and when we have the wrench set for 420lbs, it is usually within ±2lbs, most of the time within 1 lb [depends on who tests the wrench, and how smooth you pull on it until it clicks]

 

[biggy238]

I think i;m going to try and get a snap-on through the program they had with my tech school. 1/2 price.

 

[nickleinonen]

1/2 price = good deal imho. . i should have stocked up on the snap on goodies when i was in tech school, but i was poor and unemployed at the time so no go [still poor now after dropping large on a house]

 

[biggy238]

Well, I think they are betting on that so they can offer 1/2 price without having so many take advantage of it.

 

[rbattelle]

I've got an old (1997?) Craftsman 25-150 ft*lb and a new (2006) Husky 50-250 ft*lb. Both click type. I've never calibrated either of them.

If I had the money, I'd get a nice fancy one. But I just can't afford it.

Ryan

 

[BGlidewell]

...

If I had the money, I'd get a nice fancy one. But I just can't afford it.

...

I could not afford the damage caused by the cheap one I had. Now I only use one of three calibrated snap-ons (for each range being used).

 

[DJW]

Loghead, reading your post and well aware of many mechanics not trusting other types of torque wrenches, wonder in this day and age if one could come up with a device to clamp on the Beam, and when the pointer came to the predetermined poundage to ring or even light and sound. I used to set the ignition points on my 1970 Honda 4 cyl. motorcycle using a pocket transistor radio, turn the radio on and when the points made contact the radio would sound owing to static, far more accurate than the clip on bulb method. Perhaps after the design of the wireless back-up system now used in cars etc. The micro stuff they make today quite unbelievable just a few years ago.

 

[biggy238]

Looked at the Craftsman offerings tonight. The 70 dollar one is the same wrench. Different color handles.



I'd like to know who manufactures the $110 wrench and the $220 digital piece sears offers.



My Tech school had a Dial Gauge that clamped to a table that came from the avaiation lab. The practice was to put a socket on and crank it to several different points on the wrench's scale. Seems like maybe it was damaged before I left?

 

[Forrest Nearing]

I wouldn't mess w/ the Sears wrenches. check out the link I posted above... that's gonna be the best new wrench you can get for the money IMO

 

[biggy238]

I looked it over right after you posted. I was well pleased. Thank you. I just have to get myself together and buy one.

 

[DPellegrin]

Loghead you got it right!



The debate about which kind of torque wrench is best has existed for a long time. A few years ago one of the car performance magazines conducted testing to determine which kind of torque wrench was the most accurate. The contestants were: Beam type, "clicker" type, and dial indicator type. The winner was the beam type, which was also the least expensive.



All torque wrenches work on the principal of Hook's law of spring constants. Basically Hook's law says that the stress is proportional to the strain. This means, for example, that on a given steel beam if it takes 50 pounds of force to deflect the beam 1/2 inch then it will take 100 pounds of force to deflect the beam 1 inch, in fact that's how calibration is verified.



Beam type torque wrenches don't look high tech like the others, but they measure force X distance (torque) very well. If the pointer starts on "0" then you are calibrated!



Regards

 

[biggy238]

Not to say that this wouldn't affect a micrometer or dial indicator type, but why wouldn't ambient temperature have an affect on a beam type?



I live in Kentucky, and see anywhere from negative temps to 100+ degrees. At some point I would think that this would play a role.

 

[Forrest Nearing]

beam style are accurate, but they're very difficult to get an accurate pull at higher torque levels.



on a clicker, you want a good steady pull up to the torque level. there is a moment of inertia that has to be overcome, so if you're pulling towards a 100ftlb click and you have to stop due to leverage/space constraints and come back on the fastener, the wrench might click, but that doesn't mean you have 100ftlbs on the fastener. You could have 85-90ftlbs on it, but you have to apply more than 100ftlbs to overcome the moment of inertia and get the fastener moving again.



a beam style is VERY difficult to get an accurate torque at high levels. the wrench itself may be perfectly accurate, but if you're unable to apply that accurate torque, it's not really worth much

 

[rbattelle]

Of course, a torque value is only good if you know what friction condition exists in the fastener threads.

I tend to assume most torque specifications assume a well-lubricated thread.

Some interesting wisdom from Machinery's Handbook:

Bolts are often tightened by applying torque to the head or nut, which causes the bolt to stretch. The stretching results in bolt tension or preload, which is the force that holds a joint together.
Torque is relatively easy to measure with a torque wrench, so it is the most frequently used indicator of bolt tension. Unfortunately, a torque wrench does not measure bolt tension accurately, mainly because it does not take friction into account.

These facts should play into your choice of torque wrench. If the wrench is accurate to +/- 1% but you're only confident of the proper torque to within +/- 20% (owing to the lack of friction information on the torque spec), you've wasted money on the wrench for that specific application.

Ryan

 

[Forrest Nearing]

yes, but the point is, even with the correct lube, you aren't getting repeatable/accurate torque values unless you're making a smooth pull all the way to the click.



I'll use head studs because they're a critical fastener that lots of guys deal with. If you've got 5-10ftlbs variance on your lug nuts, chances are, you'll never have a problem. But with cylinder head fasteners, I want everything to be as true and even as possible.



If you're trying to grunt out 120ftlbs while bent over the front of your rig, and while pulling the wrench you run out of leverage or the wrench has run out of travel due to space constraints. When you reposition the wrench and begin to pull and get a "click" before the wrench even begins to move, you DO NOT have the correct stretch on that fastener!!!!!



back it off and re-do the torque on it. You want the wrench to click while you've got a nice smooth pull going on it.